Vent plug



1966 J. J. DAVENPORT 3,239,378

VENT PLUG Filed NOV. 23, 1964 I I I4 I2 1 r we 2| 22J I6 23 I7 Fl G.

INVENTOR:

JOSEPH DAVE ORT BY: &

HIS AGENT United tes Patent 3,289,878 VENT PLUG ware r Filed Nov. 23, 1964, Ser. No. 412,971 2 Claims. (Cl. 220-44) This invention relates to a plug adapted to be releasably secured in the bung hole of a drum container which plug comprises a vent means for preventing the development of a vacuum or a high gas pressure the drum.

It is common practice for many manufacturers to ship products, especially products of'the liquid variety, to customers in large drum-like containers. These drums have a bung hole located near the rim on "one end through which the contents of the drum are emptied. A threaded plug or bung cap is usually the means used to seal off the bung hole during shipment of the product or storage thereof. A

A pressure diiferential between the air inside the drum and the outside atmosphere often develops due to changes in temperature and atmospheric pressure. This is especially common where the product must be shipped a considerable distance to' a location having atmospheric conditions quite different from those at the location where' the product was originally placed in the drum, or where the product is loaded into the drum above ambient temperature and cools after filling and closing. Obviously, the existence of such a pressure differential can have very damaging effects upon the drum; for instance, if a vacuum develops Within the drum the drum will collapse inwardly, on the other hand, if the pressure in the drum substantially exceeds the atmospheric pressure, the drum will bulge outwardly and in some instances may even burst. Either case results in serious problems with regard to customer rejection of shipments and redrumming expenses.

To alleviate these problems, and especially to prevent the more common occurrence of a vacuum within the drum, many venting devices for use in connection with (or as an integral part of) the aforementioned bung caps have been developed. Among the more common of these devices are the spring-loaded ball valves and various types of rubber vent plugs. One disadvantage of these prior art vent plugs is that they have a high relieving pressure and only prevent the formation of a vacuum within the drum; thus, there is still the possibility that the drum will bulge or burst when the atmospheric pressure drops below the pressure inside the drum. A more serious disadvantage of existing vacuum relief valves is their high incidence of failure with regard to drum shipment of the many sticky resin solutions which are finding ever increasing application in various industries. These sticky solutions deposit resin on the existing vacuum relief valves which clog and render the valves inoperative. Ultimately, this results in collapse of the drum due to the vacuum created therein and necessitates a costly redrumming operation to restore the drum to its proper shape. In many cases this drum deformation problem has led to customer rejection of the product due to the unsightly appearance of the drum container.

The ultimate and primary object of this invention is to provide an uncomplicated vent plug which will overcome the many aforementioned disadvantages of existing vent plugs, and which can be easily and inexpensively constructed.

Broadly, the invention comprises a vented closure or plug having a movably mounted disk means mounted in a bore which extends longitudinally through the plug. The disk means can alternatively assume a first position per- 3,289,878 Ratented Dec. 6,

mitting fluid passage through the bore and a second position for s ealing' ofi s 'a'id bore.

An important hammer the invention, useful when liquids liablet o'form sticky deposits are contained, resides in the use ofa fluorocarbon pu arer the valve disk. A fluorocarbon i s'usedbecause of its non-stick characte'ristic which resists the tendency 'forvarious' products, especially the aforementioned resins, togIue the valve shut. 'A" fluorocarbon polymer which is'yery "suitable for this purpose is polytetrafluoroethylene suchas that marketed under the trade designation of Teflon. I

The invention will now bed'escribed with reference to the accompanying drawings wherein? FIGURE 'l'is a vertical secti'od'of a vent structed'in accordance with the invention;

FIGURE 2 is a plan view of"the"t(alve disk of the inventio'ntand,

FIGURE? is a vertical ment of the invention.

' Referring to FIGURE 1, a preferred embodiment of the novel vent plug isshovvn" at 10. The vent'plug 10 comprises a main body member 11 having 'a top peripheral edge portion 12, which is hexagonally'shaped for gripping with a wrench, and a reduced diameter threaded'portion 13 which is a'dapted'to threadably engage the bung hole of a drum container (not shown). Preferably, the main body member 11 of the vent plug 10 is constructed of polypropylene, though metal or other suitable materials may also be used. A circular vent hole or bore 14 extends longitudinally through body member 11 to an enlarged cavity which includes an annular groove 16 having a top shoulder portion 17 and a bottom land 18-. An enlarged bore 19 extends from the land 18 to the bottom of the body member 11 and facilitates the insertion or removal of a valve disk 20.

Positioned within the groove 16 is a valve disk 20 having a flat circular central disk portion 21 and a plurality of downwardly curved leg members or tabs 22. Preferably, there are three support tabs 22 spaced at about the center portion 21 (see FIGURE 2) of the disk 20 which fit within the groove 16 with slight radial clearance in the manner shown in FIGURE 1. When the disk 20 is raised from this position shown, it engages the shoulder 17, preferably along only a thin annular band. This is effected by making the diameter of the portion 21 only slightly larger than that of the bore 14, as shown, and/or by making the shoulder 17 of limited radial extent by forming an annular, upwardly extending recess 23 about it, as also shown.

As discussed supra, the entire valve disk 20 is preferably made of a thin fluorocarbon polymer such as Teflon because of its non-stick property which resists the tendency of various products to glue the disk to the seating shoulder 17. However, where appropriate the disk 20 may be constructed of metal or other suitable material. As shown by the space 15 in FIGURE 1, the flat center portion 21 of the disk 20 is normally not in contact with the seating shoulder 17 of the groove 16 when the vent plug 10 is in an upright position. However, when the vent plug 10- is tilted toward an inverted position, the valve disk 20 moves under its own weight to a position wherein the fiat central portion 21 seats against the shoulder 17.

In operation, the vent plug 10 is threaded into the bung hole located in the top of a drum container. If a vacuum starts to develop in the drum container, air will enter through the vent hole 14, flow through the space 15 between the center portion 21 .of the disk 20 and the shoulder 17 of the groove 16 and on into the container through the enlarged bore 19. Conversely, should the pressure in the container increase, the air may flow out of the container by this same route. If the drum is tipped or .completely plug consection of a modified embodiinverted, the liquid solution in the drum will press the disk 20 against the seating shoulder 17 and prevent leakage of the liquid out of the vent hole 14.

As shown in FIGURE 3, it may be desirable to construct the support tabs22' in a manner such that the center portion 21' of the disk 20 is normally pressed into sealing engagement with the seating shoulder 17 so that the space 15 is eliminated even when-the vent plug 10 is in the upright position. Such a construction is especially desirable where the liquid in the container is very volatile and evaporates rapidly. Should a vacuum develop within the drum, air will enter through the vent hole 14 and exert sufficient pressure, to flex the tabs 22' and push the center portion 21 of the disk 20' away from the seating shoulder 17 to relieve the vacuum.

I claim as my invention;

1. A vented closure for a container comprising; 7

(a) an externally threaded body member adapted to be threadably secured in an aperture provided in the top of saidcontainer;

(b) a circular bore extending longitudinally through the center of said body member; said bore having an enlarged diameter portion at one end;

(c) a circumferential groove around said enlarged diameter portion of said bore;

(d) annular seat means in said enlarged portion and surrounding the smaller diameter portion of said bore;

(e) fluorocarbon disk means having a central portion and a plurality of pliably'resilient leg members'extending from said central portion into said groove, said leg members centrally positioning said central portion in said bore for limited axial movement from a normal position of disengagement from said seat means whereby the container enclosure is in constant communication with the atmosphere surrounding said container to an engaged position with said seat means whereby the escape of the contents of said container through said bore is prevented. 2. A vented closure for a container as set forth in claim 1 wherein said leg members are constructed to slide within said groove in directions parallel with theaxis of said bore, said sliding movement permitting said central portion to move from said normal position to said engaged position.

References Cited by the Examiner UNITED STATES PATENTS 739,929 9/1903 Ross et al 217.104 2,429,149 10/1947 Wittenberg 220-44 2,622,762 12/1952 Parsons 220-44 2,728,475 12/1955 Teeters et al. -2-.. 215-40 2,935,075 5/1960 Ringer 137-43 3,080,994 3/ 1963 Chausson 220-44 FOREIGN PATENTS 629,982 5/1936 Germany.

THERON E. CONDON, Primary Examiner.

RAPHAEL H. SCHWARTZ, Examiner. 

1. A VENTED CLOSURE FOR A CONTAINER COMPRISING: (A) AN EXTERNALLY THREADED BODY MEMBER ADAPTED TO BE THREADABLY SECURED IN AN APERTURE PROVIDED IN THE TOP OF SAID CONTAINER; (B) A CIRCULAR BORE EXTENDING LONGITUDINALLY THROUGH THE CENTER OF SAID BODY MEMBER; SAID BORE HAVING AN ENLARGED DIAMETER PORTION AT ONE END; (C) A CIRCUMFERENTIAL GROOVE AROUND SAID ENLARGED DIAMETER PORTION OF SAID BORE; (D) ANNULAR SEAT MEANS IN SAID ENLARGED PORTION AND SURROUNDING THE SMALLER DIAMETER PORTION OF SAID BORE; (E) FLUOROCARBON DISK MEANS HAVING A CENTRAL PORTION AND A PLURALITY OF PLIABLY RESILIENT LEG MEMBERS EXTENDING FROM SAID CENTRAL PORTION INTO SAID GROOVE, SAID LEG MEMBERS CENTRALLY POSITIONING SAID CENTRAL PORTION IN SAID BORE FOR LIMITED AXIAL MOVEMENT FROM A NORMAL POSITION OF DISENGAGEMENT FROM SAID SEAT MEANS WHEREBY THE CONTAINER ENCLOSURE IS IN CONSTANT COMMUNICATION WITH THE ATMOSPHERE SURROUNDING SAID CONTAINER TO AN ENGAGED POSITION WITH SAID SEAT MEANS WHEREBY THE ESCAPE OF THE CONTENTS OF SAID CONTAINER THROUGH SAID BORE IS PREVENTED. 